Vulnerabilities > CVE-2021-20235 - Out-of-bounds Write vulnerability in Zeromq Libzmq
Attack vector
NETWORK Attack complexity
HIGH Privileges required
NONE Confidentiality impact
HIGH Integrity impact
HIGH Availability impact
HIGH Summary
There's a flaw in the zeromq server in versions before 4.3.3 in src/decoder_allocators.hpp. The decoder static allocator could have its sized changed, but the buffer would remain the same as it is a static buffer. A remote, unauthenticated attacker who sends a crafted request to the zeromq server could trigger a buffer overflow WRITE of arbitrary data if CURVE/ZAP authentication is not enabled. The greatest impact of this flaw is to application availability, data integrity, and confidentiality.
Vulnerable Configurations
| Part | Description | Count |
|---|---|---|
| Application | 10 |